In sewage treatment plants, the incoming sewage, together with activated sludge, flows progressively and relatively slowly through the aerating tanks. During this time it is subjected to aeration by means of air diffusers in the tank, and the successful treatment of sewage depends heavily upon the efficient transfer of oxygen into the mixed liquor in the tank. In large tanks, the air diffusers also perform the function of inducing circulation of the liquor in the tank in a predetermined circulatory pattern. In the case of large tanks, the positioning of the air diffusers becomes critical and must be held within tight tolerances when the diffusers are installed in the tank so that the liquor to be aerated will follow the proper circulation paths for most effective aeration. For instance, with certain types of diffusers which project laterally from connectors spaced along a header, it is important, both from the standpoint of diffuser operation and liquor circulation, that the headers be accurately aligned in a horizontal direction. Heretofore this has been accomplished by various methods which were both time consuming and relatively inaccurate. Standard pipe sections and fittings are often prepared on the construction site and are installed in the best way possible. However, the tolerances associated with the use of standard fittings and techniques makes leveling and alignment in the field very difficult and inaccurate.
Accordingly, it is an object of this invention to provide improved aeration systems in sewage treatment tanks wherein the headers and diffusers can be readily brought to an accurate level position during installation without complicated alignment procedures.
A further object of this invention is to provide improved apparatus for supporting a header in an accurately aligned horizontal position within a sewage treatment tank.